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    <title>My ATCA Welcome Page</title>
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      <h1>The My ATCA sidebar</h1>
      <a onclick="welcomeClick('www.narrabri.atnf.csiro.au/myatca/help_pages/welcome_secure.html')">
	Back to the welcome page</a>
      <p>
	On the right-hand side of the My ATCA page there will always be displayed the
	My ATCA sidebar. The sidebar is made up of a number of containers, each of which
	is topped by a grey rounded bar, with a label on the left. Each container can be
	collapsed so that only the bar is displayed, by clicking on the bar itself; it
	can then be expanded by clicking on the bar again.
      </p>
      <p>
	This page will describe the contents of each available sidebar container.
      </p>
      <h2>Time</h2>
      <p>
	This container displays the current UTC time and the local sidereal time (LST)
	at the ATCA. The sidebar gets the time from your computer's clock, so if your
	clock is not set correctly, or your timezone is not correctly described, then
	these times will likely not correspond to reality.
      </p>
      <h2>Array</h2>
      <p>
	This container gives an overview of the state of the antennas in the array.
	Each of the six antennas are represented by a column, headed by the antenna
	name (CA01, CA02, ...). The values in this container are updated every 10
	seconds.
      </p>
      <p>
	Each subsequent line shows the state of the antenna:
	<ul>
	  <li>State: this is what <tt>caobs</tt> thinks the antenna is doing. It can
	    be one of:
	    <ul>
	      <li>OFF-LINE: the antenna is not currently part of the array.</li>
	      <li>DISABLED: the antenna is part of the array, but is not being
		directly controlled by <tt>caobs</tt>.</li>
	      <li>STOWED: the antenna is in the safe stow position, but is ready
		to move on command.</li>
	      <li>IDLE: the antenna is pointing at some arbitrary position, but
		is not currenty being commanded to move.</li>
	      <li>SLEWING: the antenna is currently moving towards a new
		sky position.</li>
	      <li>TRACKING: the antenna is currently tracking a sky position.</li>
	    </ul>
	    Each state is also represented by a coloured background to make it
	    easier to quickly ascertain the state of the array.</li>
	  <li>Feed: the receiver that is currently on axis. One of 16cm, 6/3cm,
	    15mm, 7mm, 3mm</li>
	  <li>Wrap: which cable wrap hemisphere the antenna is in. One of N (north)
	    or S (south).</li>
	  <li>Az: the current dial azimuth of the antenna.</li>
	  <li>El: the current dial elevation of the antenna.</li>
	</ul>
      </p>
      <h2>Source</h2>
      <p>
	This container gives some useful information about the source currently
	being observed. The source name is shown both in the container's bar and
	at the top left of the container. The coordinates of the source
	(usually RA and Dec) are shown at the bottom of the container.
      </p>
      <p>
	The rest of the information in this container pertains to the source's
	position in the sky. The hour angle (HA) indicates the difference between
	the current LST and the source's RA, and is given in hours. This value
	relies on your computer's clock being accurate, and is updated in real-time.
	The hour angle at which this source will set (Set HA) is also shown; note
	that the source will rise at the negative value of this hour angle.
	This information is then summarised as a time-to-set or time-to-rise
	figure (Set time or Rise time).
      </p>
      <p>
	These rising/setting times are all calculated based on the ATCA's
	elevation limit of 12 degrees, by default. For some observations though
	(eg. at millimetre wavelengths), the atmosphere will become a problem
	at elevations greater than this. If you want the sidebar to calculate
	the rising/setting times to a different horizon, then change the value in
	the 'Elevation at rise/set (degrees)' text input box under the 'Sidebar'
	container in the 'Preferences' tab and press <tt>Enter</tt>.
      </p>

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